With the development of Ethernet towards a multi-service carrier, particularly the increasing requirements of some services on the reliability and real-time performance of a network, the Ethernet widely adopts the manner of ring networking to improve the reliability of the network. In addition, in a protection scheme for the ring networking, it is generally required that fast protection switching can be completed within 50 ms. Currently, the technology for fast protection switching can be implemented based on the G.8032v2 protocol of the International Telecommunication Union Telecommunication Standardization Sector (ITU-T).
Based on the G.8032v2 protocol, an automatic protection switching protocol and mechanism is defined for an Ethernet Layer of a ring topological Ethernet. Such a network protection method is applied to the ring topological Ethernet and includes the following major implementation processes: in the ring topological Ethernet, a link is selected as a Ring Protection Link (RPL) and two adjacent nodes on the RPL are configured to control blockage or connection of the RPL. One of the nodes is called an RPL owner node and the other one is called an RPL neighbor node. Adjacent ports relative to the RPL on the two adjacent nodes in the RPL are called RPL ports.
When all links of an Ethernet ring network are normal, the two adjacent nodes of the RPL block the RPL ports to prevent protected data from passing through the RPL. By doing so, there is only one communication path between any two nodes in the Ethernet ring network, thus avoiding a closed loop of the communication path in the Ethernet ring network and preventing the closed loop and a network storm. When a failure occurs in a link of the Ethernet ring network, a node adjacent to the failed link blocks a fault port if the failed link is not an RPL, and two nodes adjacent to the RPL make the two RPL ports connected to enable the protected data to pass through the RPL. Therefore, a new communication path is generated between any two nodes of the RPL to guarantee reconnection of the communication path and improve the network reliability.
During an Ethernet switching process, a communication path of data flow changes. Since address table information recorded by each node may not be applicable any longer after the communication path of the data flow changes, each node may need to refresh its address table, wherein the refresh refers to delete an address item of a port on the ring. In the G.8032v2 protocol, an Ethernet ring network protection protocol frame sent by a node includes a node numbering of the node itself and an index numbering of a blocked port. After receiving the protocol frame, other nodes extract the node numbering and the index numbering of the blocked port from the protocol frame, and compare the node numbering and the index numbering of the blocked port in the protocol frame with a node numbering and an index numbering of a blocked port in refreshed record information stored for a receiving port, and if they are different, update the refreshed record information corresponding to the receiving port as the extracted node numbering and index numbering of the blocked port. In addition, if the node numbering and the index numbering of the blocked port in the protocol frame are different from the node numbering and the index numbering of the blocked port in the refreshed record information corresponding to a port opposite to the receiving port, the node may also need to refresh its address table. Moreover, when the node is blocking a port, the node needs to delete node numbering and index numbering of the blocked port in refreshed record information corresponding respectively to two ports of the node on the ring.
Although the above scheme for refreshing the address table in the Ethernet ring network guarantees that an error address item can be rapidly deleted during switching of the Ethernet ring network, it causes the problem that the address table is refreshed repeatedly during the switching. For example, during a switchback process upon recovery of the link from failure, after blocking an RPL port, the RPL owner node sends a No Request RPL Blocked (NRRB) protocol frame. After the RPL Port receives the RPLB protocol frame, since a node numbering and an index numbering of a blocked port in the RPLB protocol frame are different from a node numbering and an index numbering of a blocked port in refreshed record information corresponding to a receiving port, the RPL Port updates the refreshed record information corresponding to a receiving port as the received node numbering and index numbering of the blocked port. In addition, since the node numbering and the index numbering of the blocked port in the received RPLB protocol frame are also different from a node numbering and an index numbering of a blocked port in refreshed record information corresponding to a port opposite to the receiving port, the RPL Port updates the address table according to an address refreshing principle of the Ethernet ring network.
Subsequently, RPL neighbor node further needs to block the RPL Port and delete the node numbering and index numbering of the blocked port in the refreshed record information corresponding respectively to two ports of the RPL neighbor node on the ring. Since the RPL owner node will send an RPL Blocked (RPLB) protocol frame continuously, the RPL neighbor node, after receiving a subsequent RPL blocked protocol frame, will refresh the address table over again because its two ports do not have refreshed record information. However, the address table refreshing operation is unnecessary actually and may possibly cause a burst of network traffic because there are too many involved nodes and users, which hampers effective utilization of network recourses and normal operation of user services.